Some conventional plasma processing apparatus use an electrostatic chuck in order to fix a wafer in a chamber. In a method using this electrostatic chuck, a high DC voltage is applied to the electrostatic chuck to cause a Coulomb force to act on the wafer, thereby fixing the wafer.
In such a plasma processing apparatus, the application of the high DC voltage to the electrostatic chuck under the condition without any plasma causes the surface of the wafer to adsorb particles due to the Coulomb force acting on the wafer. Therefore, at the start of the process, the high DC voltage to the electrostatic chuck is turned on after an RF power is turned on, and at the completion of the process, the RF power is turned off after the high DC voltage to the electrostatic chuck is turned off, thereby preventing the high DC voltage from being applied to the electrostatic chuck under the condition without any plasma to reduce the adhesion of the particles to the surface of the wafer.
In this method, however, due to the exposure of the wafer to the plasma even after the high DC voltage to the electrostatic chuck is turned off, etching progresses up to an etching amount exceeding a desired amount, thereby giving an adverse effect to the finished shape size, and so on, which has posed a problem of deteriorating device performance.